IDH2 stabilizes HIF-1α-induced metabolic reprogramming and promotes chemoresistance in urothelial cancer.

Drug resistance contributes to poor therapeutic response in urothelial carcinoma (UC). Metabolomic analysis suggested metabolic reprogramming in gemcitabine-resistant urothelial carcinoma cells, whereby increased aerobic glycolysis and metabolic stimulation of the pentose phosphate pathway (PPP) promoted pyrimidine biosynthesis to increase the production of the gemcitabine competitor deoxycytidine triphosphate (dCTP) that diminishes its therapeutic effect. Furthermore, we observed that gain-of-function of isocitrate dehydrogenase 2 (IDH2) induced reductive glutamine metabolism to stabilize Hif-1α expression and consequently stimulate aerobic glycolysis and PPP bypass in gemcitabine-resistant UC cells. Interestingly, IDH2-mediated metabolic reprogramming also caused cross resistance to CDDP, by elevating the antioxidant defense via increased NADPH and glutathione production. Downregulation or pharmacological suppression of IDH2 restored chemosensitivity. Since the expression of key metabolic enzymes, such as TIGAR, TKT, and CTPS1, were affected by IDH2-mediated metabolic reprogramming and related to poor prognosis in patients, IDH2 might become a new therapeutic target for restoring chemosensitivity in chemo-resistant urothelial carcinoma.

Vasohibin-1 Expression Can Predict Pathological Complete Remission of Advanced Bladder Cancer with Neoadjuvant Chemotherapy.

BACKGROUND AND PURPOSE: Neoadjuvant chemotherapy (NAC) is a well-established standard practice in invasive bladder cancer (BCa), however patient selection remains challenging. High expression of vasohibin-1 (VASH1), an endogenous regulator of angiogenesis, has been reported in high-grade and advanced BCa; however, its prognostic value for chemotherapy outcomes remains unexplored. In this study, we sought to identify biomarkers of chemotherapy response focusing on the relationship between angiogenesis and tissue hypoxia. METHODS: Forty Japanese patients with BCa who underwent NAC and radical cystectomy were included in the present analysis. We compared the immunohistochemical expression of CD34, VASH1, and carbonic anhydrase 9 (CA9) between patients who achieved tumor clearance at operation (ypT0) and those with residual disease after cystectomy. RESULTS: There were 19 patients in the ypT0 group, while the remaining 21 patients had residual tumors at operation. Patients in the ypT0 group had high microvessel density (p = 0.031), high VASH1 density (p < 0.001), and stronger CA9 staining (p = 0.046) than their counterparts. Multivariate analysis identified microvessel and VASH1 density as independent predictive factors for pathological ypT0 disease (p = 0.043 and 0.002, respectively). The 5-year recurrence-free survival rate was higher in the high VASH1 density group than in the low VASH1 density group (66.3% vs. 33.3%, p = 0.036). CONCLUSION: VASH1 density is a potential therapeutic biomarker for chemotherapy response in BCa.

Memory B Cells and Memory T Cells Induced by SARS-CoV-2 Booster Vaccination or Infection Show Different Dynamics and Responsiveness to the Omicron Variant.

Although the immunological memory produced by BNT162b2 vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been well studied and established, further information using different racial cohorts is necessary to understand the overall immunological response to vaccination. We evaluated memory B and T cell responses to the severe acute respiratory syndrome coronavirus 2 spike protein before and after the third booster using a Japanese cohort. Although the Ab titer against the spike receptor-binding domain (RBD) decreased significantly 8 mo after the second vaccination, the number of memory B cells continued to increase, whereas the number of memory T cells decreased slowly. Memory B and T cells from unvaccinated infected patients showed similar kinetics. After the third vaccination, the Ab titer increased to the level of the second vaccination, and memory B cells increased at significantly higher levels before the booster, whereas memory T cells recovered close to the second vaccination levels. In memory T cells, the frequency of CXCR5+CXCR3+CCR6- circulating follicular Th1 was positively correlated with RBD-specific Ab-secreting B cells. For the response to variant RBDs, although 60-80% of memory B cells could bind to the omicron RBD, their avidity was low, whereas memory T cells show an equal response to the omicron spike. Thus, the persistent presence of memory B and T cells will quickly upregulate Ab production and T cell responses after omicron strain infection, which prevents severe illness and death due to coronavirus disease 2019.

Pericentromeric noncoding RNA changes DNA binding of CTCF and inflammatory gene expression in senescence and cancer.

Cellular senescence causes a dramatic alteration of chromatin organization and changes the gene expression profile of proinflammatory factors, thereby contributing to various age-related pathologies through the senescence-associated secretory phenotype (SASP). Chromatin organization and global gene expression are maintained by the CCCTC-binding factor (CTCF); however, the molecular mechanism underlying CTCF regulation and its association with SASP gene expression remains unclear. We discovered that noncoding RNA (ncRNA) derived from normally silenced pericentromeric repetitive sequences directly impairs the DNA binding of CTCF. This CTCF disturbance increases the accessibility of chromatin and activates the transcription of SASP-like inflammatory genes, promoting malignant transformation. Notably, pericentromeric ncRNA was transferred into surrounding cells via small extracellular vesicles acting as a tumorigenic SASP factor. Because CTCF blocks the expression of pericentromeric ncRNA in young cells, the down-regulation of CTCF during cellular senescence triggers the up-regulation of this ncRNA and SASP-related inflammatory gene expression. In this study, we show that pericentromeric ncRNA provokes chromosomal alteration by inhibiting CTCF, leading to a SASP-like inflammatory response in a cell-autonomous and non-cell-autonomous manner and thus may contribute to the risk of tumorigenesis during aging.

The membrane-linked adaptor FRS2ß fashions a cytokine-rich inflammatory microenvironment that promotes breast cancer carcinogenesis.

Although it is held that proinflammatory changes precede the onset of breast cancer, the underlying mechanisms remain obscure. Here, we demonstrate that FRS2ß, an adaptor protein expressed in a small subset of epithelial cells, triggers the proinflammatory changes that induce stroma in premalignant mammary tissues and is responsible for the disease onset. FRS2ß deficiency in mouse mammary tumor virus (MMTV)-ErbB2 mice markedly attenuated tumorigenesis. Importantly, tumor cells derived from MMTV-ErbB2 mice failed to generate tumors when grafted in the FRS2ß-deficient premalignant tissues. We found that colocalization of FRS2ß and the NEMO subunit of the IκB kinase complex in early endosomes led to activation of nuclear factor-κB (NF-κB), a master regulator of inflammation. Moreover, inhibition of the activities of the NF-κB-induced cytokines, CXC chemokine ligand 12 and insulin-like growth factor 1, abrogated tumorigenesis. Human breast cancer tissues that express higher levels of FRS2ß contain more stroma. The elucidation of the FRS2ß-NF-κB axis uncovers a molecular link between the proinflammatory changes and the disease onset.

Assessing anti-SARS-CoV-2 cellular immunity in 571 vaccines by using an IFN-γ release assay.

Memory T cell responses have been analyzed only in small cohorts of COVID-19 vaccines. Herein, we aimed to assess anti-SARS-CoV-2 cellular immunity in a large cohort using QuantiFERON assays, which are IFN-γ release assays (IGRAs) based on short-term whole blood culture. The study included 571 individuals receiving the viral spike (S) protein-expressing BNT162b2 mRNA vaccine. QuantiFERON assays revealed antigen-specific IFN-γ production in most individuals 8 weeks after the second dose. Simultaneous flow cytometric assays to detect T cells expressing activation-induced markers (AIMs) performed for 28 randomly selected individuals provided data correlating with the QuantiFERON data. Simultaneous IFN-γ enzyme-linked immunospot and AIM assays for another subset of 31 individuals, based on short-term peripheral blood mononuclear cell culture, also indicated a correlation between IFN-γ production and AIM positivity. These observations indicated the acquisition of T cell memory responses and supported the usability of IGRAs to assess cellular immunity. The QuantiFERON results were weakly correlated with serum IgG titers against the receptor-binding domain of the S protein and were associated with pre-vaccination infection and adverse reactions after the second dose. The present study revealed cellular immunity after COVID-19 vaccination, providing insights into the effects and adverse reactions of vaccination.

Tumor Burden Monitoring with Circulating Tumor DNA During Treatment in Patients with Esophageal Squamous Cell Carcinoma.

BACKGROUND: To guide appropriate treatment strategy, an accurate tumor monitoring modality that reflects tumor burden during neoadjuvant treatment is required for esophageal squamous cell carcinoma (ESCC). We aimed to investigate the clinical utility of circulating tumor DNA (ctDNA) in plasma in patients who received neoadjuvant chemotherapy (NAC) followed by esophagectomy. PATIENTS AND METHODS: Longitudinally collected plasma samples for ctDNA combined with genomic DNA from primary lesions were obtained from patients with histologically confirmed ESCC who underwent NAC followed by subtotal esophagectomy. Next-generation sequencing was performed to identify mutations from the plasma and the primary tumor. The relationships between changes in ctDNA and the pathological response and recurrence were assessed in patients with locally advanced ESCC. RESULTS: In pretreatment samples from 13 patients, multiple concordant mutations in ctDNA and primary tumors were observed in 11 patients (85%), who were classified as ctDNA positive before treatment. The ctDNA positive rate after NAC correlated with the pathological response (responders, 25%; nonresponders, 100%; p = 0.007). The risk of recurrence increased significantly in patients with positive ctDNA after surgery in analysis of 16 patients; the 1-year recurrence-free survival rates were 90 and 0% in ctDNA-negative and ctDNA-positive groups, respectively (p = 0.0008). In two patients with postoperative recurrence, ctDNA was detected approximately 5.5 months earlier than the diagnosis using radiographical imaging. CONCLUSIONS: ctDNA is a promising biomarker for predicting pathological response and postoperative recurrence in ESCC. To demonstrate the external validity, we are currently preparing a multicenter prospective study.

MEK inhibition suppresses metastatic progression of KRAS-mutated gastric cancer.

Metastatic progression of tumors is driven by genetic alterations and tumor-stroma interaction. To elucidate the mechanism underlying the oncogene-induced gastric tumor progression, we have developed an organoid-based model of gastric cancer from GAstric Neoplasia (GAN) mice, which express Wnt1 and the enzymes COX2 and microsomal prostaglandin E synthase 1 in the stomach. Both p53 knockout (GAN-p53KO) organoids and KRASG12V -expressing GAN-p53KO (GAN-KP) organoids were generated by genetic manipulation of GAN mouse-derived tumor (GAN wild-type [WT]) organoids. In contrast with GAN-WT and GAN-p53KO organoids, which manifested Wnt addiction, GAN-KP organoids showed a Wnt-independent phenotype and the ability to proliferate without formation of a Wnt-regulated three-dimensional epithelial architecture. After transplantation in syngeneic mouse stomach, GAN-p53KO cells formed only small tumors, whereas GAN-KP cells gave rise to invasive tumors associated with the development of hypoxia as well as to liver metastasis. Spatial transcriptomics analysis suggested that hypoxia signaling contributes to the metastatic progression of GAN-KP tumors. In particular, such analysis identified a cluster of stromal cells located at the tumor invasive front that expressed genes related to hypoxia signaling, angiogenesis, and cell migration. These cells were also positive for phosphorylated extracellular signal-regulated kinase (ERK), suggesting that mitogen-activated protein kinase (MAPK) signaling promotes development of both tumor and microenvironment. The MEK (MAPK kinase) inhibitor trametinib suppressed the development of GAN-KP gastric tumors, formation of a hypoxic microenvironment, tumor angiogenesis, and liver metastasis. Our findings therefore establish a rationale for application of trametinib to suppress metastatic progression of KRAS-mutated gastric cancer.

Development of an in vitro carcinogenesis model of human papillomavirus-induced cervical adenocarcinoma.

Cervical adenocarcinoma (ADC) is the second most common pathological subtype of cervical cancer after squamous cell carcinoma. It accounts for approximately 20% of cervical cancers, and the incidence has increased in the past few decades, particularly among young patients. The persistent infection of high-risk human papillomavirus (HPV) is responsible for most cervical ADC. However, almost all available in vitro models are designed to study the carcinogenesis of cervical squamous cell carcinoma. To gain better insights into molecular background of ADC, we aimed to establish an in vitro carcinogenesis model of ADC. We previously reported the establishment of an in vitro model for cervical squamous cell carcinoma by introducing defined viral and cellular oncogenes, HPV16 E6 and E7, c-MYC, and activated RAS to human cervical keratinocytes. In this study, the expression of potential lineage-specifying factors and/or SMAD4 reduction was introduced in addition to the defined four oncogenes to direct carcinogenesis toward ADC. The cell properties associated with the cell lineage were analyzed in monolayer and organoid cultures and the tumors in mouse xenografts. In the cells expressing Forkhead box A2 (FOXA2), apparent changes in cell properties were observed, such as elevated expression of columnar cell markers and decreased expression of squamous cell markers. Strikingly, the histopathology of tumors expressing FOXA2 resembled cervical ADC, proposing that FOXA2 plays a vital role in dictating the histopathology of cervical cancers.

Immune evasion and chronological decrease in titer of neutralizing antibody against SARS-CoV-2 and its variants of concerns in COVID-19 patients.

Many variants of SARS-CoV-2 have emerged, and decreased neutralizing antibodies after vaccination and breakthrough infections have become a problem. The importance of monitoring titers of neutralizing antibodies is getting higher. We enrolled 146 COVID-19 patients, who were thought to be infected with Wuhan-hu-1 or D614G strains, and examined the time course of neutralizing titers against six concerning strains (Wuhan-hu-1, Alpha, Beta, Gamma, Kappa, and Delta) using newly developed ELISA. The acquisition of neutralizing titer was positively associated with disease severity. Immune evasions were observed approximately 20 to 30% for Alpha, Kappa, and Delta variant, and 40 to 45% for Beta and Gamma variant. The titers against all strains decreased over time, and interestingly, while titers against Wuhan-hu-1 decreased by 23%, those to Delta variant decreased by 70%. Our simple, cost-effective, and non-hazardous system will be applicable to process numerous samples, such as monitoring titers against prevalent strains after infection or vaccination.

Impact of coronavirus disease 2019 on the number of newly diagnosed cancer patients and examinations and surgeries performed for cancer in Japan: a nationwide study.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has rapidly and dramatically influenced healthcare across Japan. However, the influence of the COVID-19 pandemic on the number of newly diagnosed cancer, surgical treatment, and diagnostic examination for cancer types have not been completely investigated all over Japan. This study aimed to analyze the number of cases before and during the COVID-19 pandemic. METHODS: This retrospective study was a survey that asked to provide the number of cases diagnosed with gastric, colorectal, lung, breast, and cervical cancer between January 2019 and December 2020. The survey was sent to tertiary healthcare hospitals, including national cancer institutions, university hospitals, and general hospitals, all over Japan. Data obtained from 105 of 486 surveyed hospitals were evaluated, and the number of cases in each quarter in 2020 was compared with that in the equivalent quarter in 2019. RESULTS: In the second quarter (Q2), significant reductions were observed in the median number of newly diagnosed cases from 2019 to 2020: gastric cancer, 26.7% (43 vs. 32, p <  0.001); colorectal cancer, 17.9% (52 vs. 40, p <  0.001); lung cancer, 12.3% (53.5 vs. 47, p <  0.001); and breast cancer, 13.1% (43 vs. 35.5, p <  0.001). A significant reduction of 11.4% (9 vs. 8, p = 0.03) was observed in the third quarter (Q3) for cervical cancer. In Q2, the number of cases decreased by 30.9% (25 vs. 15, p <  0.001) for stage I gastric cancer, by 27.3% (12 vs. 9, p <  0.001) for stage I colorectal cancer, and by 17.6% (13 vs. 10, p <  0.001) for stage II breast cancer. The magnitude of reduction was significant for the localized stages of gastric, colorectal, and breast cancer according to diagnostic examinations in Q2 and surgical and endoscopic treatment in Q3 rather than that for lung or cervical cancer. CONCLUSIONS: COVID-19 has prolonged collateral effects on cancer care, including examination, diagnosis, and surgery, with significant effects on gastric cancer, followed by colorectal, lung, breast, and cervical cancer in Japan.

Modulation of Nogo receptor 1 expression orchestrates myelin-associated infiltration of glioblastoma.

As the clinical failure of glioblastoma treatment is attributed by multiple components, including myelin-associated infiltration, assessment of the molecular mechanisms underlying such process and identification of the infiltrating cells have been the primary objectives in glioblastoma research. Here, we adopted radiogenomic analysis to screen for functionally relevant genes that orchestrate the process of glioma cell infiltration through myelin and promote glioblastoma aggressiveness. The receptor of the Nogo ligand (NgR1) was selected as the top candidate through Differentially Expressed Genes (DEG) and Gene Ontology (GO) enrichment analysis. Gain and loss of function studies on NgR1 elucidated its underlying molecular importance in suppressing myelin-associated infiltration in vitro and in vivo. The migratory ability of glioblastoma cells on myelin is reversibly modulated by NgR1 during differentiation and dedifferentiation process through deubiquitinating activity of USP1, which inhibits the degradation of ID1 to downregulate NgR1 expression. Furthermore, pimozide, a well-known antipsychotic drug, upregulates NgR1 by post-translational targeting of USP1, which sensitizes glioma stem cells to myelin inhibition and suppresses myelin-associated infiltration in vivo. In primary human glioblastoma, downregulation of NgR1 expression is associated with highly infiltrative characteristics and poor survival. Together, our findings reveal that loss of NgR1 drives myelin-associated infiltration of glioblastoma and suggest that novel therapeutic strategies aimed at reactivating expression of NgR1 will improve the clinical outcome of glioblastoma patients.

Molecular and cellular mechanisms underlying brain metastasis of breast cancer.

Metastasis of cancer cells to the brain occurs frequently in patients with certain subtypes of breast cancer. In particular, patients with HER2-positive or triple-negative breast cancer are at high risk for the development of brain metastases. Despite recent advances in the treatment of primary breast tumors, the prognosis of breast cancer patients with brain metastases remains poor. A better understanding of the molecular and cellular mechanisms underlying brain metastasis might be expected to lead to improvements in the overall survival rate for these patients. Recent studies have revealed complex interactions between metastatic cancer cells and their microenvironment in the brain. Such interactions result in the activation of various signaling pathways related to metastasis in both cancer cells and cells of the microenvironment including astrocytes and microglia. In this review, we focus on such interactions and on their role both in the metastatic process and as potential targets for therapeutic intervention.

Oncogenic KRAS-expressing organoids with biliary epithelial stem cell properties give rise to biliary tract cancer in mice.

Biliary tract cancer (BTC) arises from biliary epithelial cells (BECs) and includes intrahepatic cholangiocarcinoma (IHCC), gallbladder cancer (GC), and extrahepatic cholangiocarcinoma (EHCC). Although frequent KRAS mutations and epigenetic changes at the INK4A/ARF locus have been identified, the molecular pathogenesis of BTC is unclear and the development of corresponding anticancer agents remains inadequate. We isolated epithelial cell adhesion molecule (EpCAM)-positive BECs from the mouse intrahepatic bile duct, gallbladder, and extrahepatic bile duct, and established organoids derived from these cells. Introduction of activated KRAS and homozygous deletion of Ink4a/Arf in the cells of each organoid type conferred the ability to form lethal metastatic adenocarcinoma with differentiated components and a pronounced desmoplastic reaction on cell transplantation into syngeneic mice, indicating that the manipulated cells correspond to BTC-initiating cells. The syngeneic mouse models recapitulate the pathological features of human IHCC, GC, and EHCC, and they should therefore prove useful for the investigation of BTC carcinogenesis and the development of new therapeutic strategies. Tumor cells isolated from primary tumors formed organoids in three-dimensional culture, and serial syngeneic transplantation of these cells revealed that their cancer stem cell properties were supported by organoid culture, but not by adherent culture. Adherent culture thus attenuated tumorigenic activity as well as the expression of both epithelial and stem cell markers, whereas the expression of epithelial-mesenchymal transition (EMT)-related transcription factor genes and mesenchymal cell markers was induced. Our data show that organoid culture is important for maintenance of epithelial cell characteristics, stemness, and tumorigenic activity of BTC-initiating cells.

Deficiency of large tumor suppressor kinase 1 causes congenital hearing loss associated with cochlear abnormalities in mice.

Mammalian auditory hair cells are not spontaneously replaced. Their number and coordinated polarization are fairly well-maintained and both these factors might be essential for the cochlear amplifier. Cell cycle regulation has critical roles in regulating appropriate cell size and cell number. However, little is known about the physiological roles of the Hippo pathway, which is one of the most important signaling cascades that regulates cell growth, differentiation, and regenerative capacity in the cochlear sensory epithelium. Herein, we investigated the in vivo role of the large tumor suppressor 1 (LATS1), an essential kinase in the Hippo/yes-associated protein pathway, in the cochlea using the LATS1 knockout mice. LATS1 was expressed in hair cells and supporting cells. It was strongly expressed on the surface of the cuticular plate of the organ of Corti. We found that LATS1 knockout caused congenital hearing loss due to the irregular orientation and slightly reduced number of hair cells, whereas the number of supporting cells remained unchanged. On the surface of the hair cells, the kinocilium and stereocilia were dispersed during and after morphogenesis. However, the expression of the receptor-independent polarity regulators, such as Par3 or Gαi, was not affected. We concluded that LATS1 has an indispensable role in the maturation of mammalian auditory hair cells, but not in the development of the supporting cells, and thus, has a role in the hearing acquisition.

The insulin-PI3K-Rac1 axis contributes to terminal adipocyte differentiation through regulation of actin cytoskeleton dynamics.

Adipocyte differentiation is accompanied by a pronounced change in the actin cytoskeleton characterized by the reorganization of filamentous (F)-actin stress fibers into cortical F-actin structures. We previously showed that depolymerization of F-actin stress fibers induced by inactivation of RhoA-ROCK (Rho-associated kinase) signaling acts as a trigger for adipocyte differentiation. The relevance and underlying mechanism of the formation of cortical F-actin structures from depolymerized actin during adipocyte differentiation have remained unclear, however. We have now examined the mechanistic relation between actin dynamics and adipogenic induction. Transient exposure to the actin-depolymerizing agent latrunculin A (LatA) supported the formation of adipocyte-associated cortical actin structures and the completion of terminal adipocyte differentiation in the presence of insulin, whereas long-term exposure to LatA prevented such actin reorganization as well as terminal adipogenesis. Moreover, these effects of insulin were prevented by inhibition of phosphatidylinositol 3-kinase (PI3K)-Rac1 signaling and the actin-related protein 2/3 (Arp2/3) complex which is a critical component of the cortical actin networks. Our findings thus suggest that the insulin-PI3K-Rac1 axis leads to the formation of adipocyte-associated cortical actin structures which is essential for the completion of adipocyte differentiation.

Targeting of cancer stem cells by differentiation therapy.

Chemoresistance is a hallmark of cancer stem cells (CSCs). To develop novel therapeutic strategies that target CSCs, we established osteosarcoma-initiating (OSi) cells by introducing the c-Myc gene into bone marrow stromal cells derived from Ink4a/Arf KO mice. These OSi cells include bipotent committed cells (similar to osteochondral progenitor cells) with a high tumorigenic activity as well as tripotent cells (similar to mesenchymal stem cells) of low tumorigenicity. We recently showed that the tripotent OSi cells are highly resistant to chemotherapeutic agents, and that depolymerization of the actin cytoskeleton in these cells induces their terminal adipocyte differentiation and suppresses their tumorigenicity. We here provide an overview of modulation of actin cytoskeleton dynamics associated with terminal adipocyte differentiation in osteosarcoma as well as discuss the prospects for new therapeutic strategies that target chemoresistant CSCs by inducing their differentiation.

Vasodilator oxyfedrine inhibits aldehyde metabolism and thereby sensitizes cancer cells to xCT-targeted therapy.

The major cellular antioxidant glutathione (GSH) protects cancer cells from oxidative damage that can lead to the induction of ferroptosis, an iron-dependent form of cell death triggered by the aberrant accumulation of lipid peroxides. Inhibitors of the cystine-glutamate antiporter subunit xCT, which mediates the uptake of extracellular cystine and thereby promotes GSH synthesis, are thus potential anticancer agents. However, the efficacy of xCT-targeted therapy has been found to be diminished by metabolic reprogramming that affects redox status in cancer cells. Identification of drugs for combination with xCT inhibitors that are able to overcome resistance to xCT-targeted therapy might thus provide the basis for effective cancer treatment. We have now identified the vasodilator oxyfedrine (OXY) as a sensitizer of cancer cells to GSH-depleting agents including the xCT inhibitor sulfasalazine (SSZ). Oxyfedrine contains a structural motif required for covalent inhibition of aldehyde dehydrogenase (ALDH) enzymes, and combined treatment with OXY and SSZ was found to induce accumulation of the cytotoxic aldehyde 4-hydroxynonenal and cell death in SSZ-resistant cancer cells both in vitro and in vivo. Microarray analysis of tumor xenograft tissue showed cyclooxygenase-2 expression as a potential biomarker for the efficacy of such combination therapy. Furthermore, OXY-mediated ALDH inhibition was found to sensitize cancer cells to GSH depletion induced by radiation therapy in vitro. Our findings thus establish a rationale for repurposing of OXY as a sensitizing drug for cancer treatment with agents that induce GSH depletion.

Overexpression of a panel of cancer stem cell markers enhances the predictive capability of the progression and recurrence in the early stage cholangiocarcinoma.

BACKGROUND: Cancer recurrence is the important problem of cholangiocarcinoma (CCA) patients, lead to a very high mortality rate. Therefore, the identification of candidate markers to predict CCA recurrence is needed in order to effectively manage the disease. This study aims to examine the predictive value of cancer stem cell (CSC) markers on the progression and recurrence of CCA patients. METHODS: The expression of 6 putative CSC markers, cluster of differentiation 44 (CD44), CD44 variant 6 (CD44v6), CD44 variants 8-10 (CD44v8-10), cluster of differentiation 133 (CD133), epithelial cell adhesion molecule (EpCAM), and aldehyde dehydrogenase 1A1 (ALDH1A1), was investigated in 178 CCA tissue samples using immunohistochemistry (IHC) and analyzed with respect to clinicopathological data and patient outcome including recurrence-free survival (RFS) and overall survival (OS). The candidate CSC markers were also investigated in serum from CCA patients, and explored for their predictive ability on CCA recurrence. RESULTS: Elevated protein level of CD44 and positive expression of CD44v6 and CD44v8-10 were significantly associated with short RFS and OS, while high levels of ALDH1A1 were correlated with a favorable prognosis patient. The elevated CD44v6 level was also correlated with higher tumor staging, whereas a decreasing level of ALDH1A1 was correlated with lower tumor staging. The levels of CD44, CD44v6 and CD44v8-10 were also correlated and were associated with a poor outcome. Furthermore, soluble CD44, CD44v6, CD44v8-10 and EpCAM were significantly increased in the recurrence group for early stage CCA; they also correlated with high levels of the tumor marker CA19-9. Elevated levels of CD44, CD44v6, CD44v8-10 or EpCAM alone or in combination has the potential to predict CCA recurrence. CONCLUSIONS: The overexpression of CD44, CD44v6, CD44v8-10 and EpCAM increases predictability of post-operative CCA recurrence. Moreover, the overexpression of the panel of CSC markers combined with CA19-9 could improve our predictive ability for tumor recurrence in early stage CCA patients. This result may be beneficial for the patients in order to predict the outcome after treatment and may be useful for clinical intervention in order to improve patient survival.

DNA damage signaling triggers degradation of histone methyltransferases through APC/C(Cdh1) in senescent cells.

Both the DNA damage response (DDR) and epigenetic mechanisms play key roles in the implementation of senescent phenotypes, but very little is known about how these two mechanisms are integrated to establish senescence-associated gene expression. Here we show that, in senescent cells, the DDR induces proteasomal degradation of G9a and GLP, major histone H3K9 mono- and dimethyltransferases, through Cdc14B- and p21(Waf1/Cip1)-dependent activation of APC/C(Cdh1) ubiquitin ligase, thereby causing a global decrease in H3K9 dimethylation, an epigenetic mark for euchromatic gene silencing. Interestingly, induction of IL-6 and IL-8, major players of the senescence-associated secretory phenotype (SASP), correlated with a decline of H3K9 dimethylation around the respective gene promoters and knockdown of Cdh1 abolished IL-6/IL-8 expression in senescent cells, suggesting that the APC/C(Cdh1)-G9a/GLP axis plays crucial roles in aspects of senescent phenotype. These findings establish a role for APC/C(Cdh1) and reveal how the DDR integrates with epigenetic processes to induce senescence-associated gene expression.